1. Field of the Invention
This invention relates to a disk player, and more particularly to a disk player such as a CD player, an LD player and a CD-V player which has an improved level search system.
2. Description of the Prior Art
Generally, such a disk player has a function of programming the sequence of playing back two or more pieces of music or songs (hereinafter, referred to as merely "songs") which are respectively recorded in sections of a disk (e.g., a so-called compact disk). Before performing quick listening of such programmed songs or setting of the recording level for dubbing them to a cassette tape or the like, it is desirable to sequentially search each of the programmed songs to confirm their output levels. Hereinafter, such a search is referred to as "a level search".
Referring to FIG. 6, the level search in a conventional CD player will be described.
When a compact disk is loaded in the CD player, initialization is performed in step N1; that is, data recorded in the table of contents (TOC) on the inside track of the disk is read. Next, the songs to be played back are selected by performing a so-called programming operation, more specifically the song numbers of the songs to be played back are selected and stored in a suitable memory device (step N2), and then the level search mode is set by pressing a level search key (step N3),
In the level search mode, a long search in which the optical head or pickup jumps to the beginning of the first one of the programmed songs which are selected in step N2 is conducted, and the first song is played back from the beginning for a fixed period of time, e.g., 100 ms, (step N4). Next, the optical pickup jumps a prefixed number of tracks (e.g., 40 tracks), and playback is performed for 100 ms (step N5). In step N6, the subcode included in the playback signal obtained in step N5 is checked whether or not the song number has changed. If the song number has not changed, then processing returns to step N5 so that the optical pickup jumps further 40 tracks and playback is performed again for 100 ms.
If it is judged in step N6 that the song number has changed, then it is checked in step N7 whether or not the song number obtained in step N5 is the next programmed song number. When the obtained song number is the next programmed song number, then processing returns to step N5. If the obtained song number is not the next programmed song number, then it is checked whether or not the obtained song number is the last programmed number (i.e., all of the programmed songs have been played back) (step N8). If YES, then the operation of the level search stops (step N9). If NO, then the optical pickup is jumped to the beginning of the next programmed song which is in turn played back for 100 ms from the beginning (step N10). Processing then returns to step N5. The output signals in steps N4, N5 and N10 are processed to obtain the output level of the programmed songs, and the output level for the programmed songs is determined.
In a level search in such a prior art CD player, the beginning of a programmed song is searched, and then operations in which a fixed number of tracks is jumped and the song is played back for a fixed period of time are repeated until the optical pickup reaches the next song. When the level search for the song has been completed, the beginning of the next programmed song is searched, and the same operations (i.e., a fixed number of tracks is jumped and playback is performed for a fixed period of time) are repeated, whereby the recording level can be set based on the playback signal obtained from playing back the songs.
In a level search of such a prior art disk player, irrespective of the lengths of the programmed songs, the number of tracks which are skipped in one jump of the optical pickup is fixed at a predetermined value (e.g., 40 tracks). When a compact disk including short songs (e.g., about 20 sec. or less) is subjected to a level search in a disk player, therefore, such short songs may be skipped even when such songs are programmed ones, resulting in that the level search cannot be conducted correctly.
Moreover, in the level search of the prior art, track jump and playback are repeated until the song changes, that is, until a time when the optical pickup jumps to one of the tracks of the next song and the song change is detected based on the data reproduced from the track. If the next song is not a programmed song, therefore, a song which does not have to be played back is unnecessarily played back.
FIG. 7 illustrates diagrammatically typical example of this kind of search, wherein PNO is the number of a programmed song and TNO is the number of a recorded song. As indicated by arrows in FIG. 7, the track jump and playback are performed in sequence three times from the beginning of the first programmed song PNO=01. Then, tracks are skipped and playback is performed for a fourth time, but in the fourth operation, the optical pickup jumps to the next song which is not programmed, i.e., song TNO=02 shown by the arrow of broken line), end playback is performed in non-programmed song TNO=02.
Similarly, in the level search of the second programmed song PNO=02, the optical pickup jumps to the next song TNO=04 which is=not programmed, and playback is performed in the song TNO=04.
In this way, in a level search of the prior art, songs which are not programmed are unnecessarily played back, and the recording level is set based on output signals obtained in playback operations including these unnecessary playback operations, resulting a situation where the recording level cannot be accurately set.